Question: The perimeter of a rectangle is $90$ centimeters. The length is $27$ centimeters. What is the width of the rectangle?
Answer: Perimeter is the distance around a closed figure. We can find the perimeter of a shape by adding all the side lengths. The perimeter is $90}\text{ cm}$ and the length is ${27}\text{ cm}$. $27\text{ cm}$ $27\text{ cm}$ $\text{Perimeter}= 90\text{ centimeters}\,$ $\,{w}$ $\,{w}$ $\begin{aligned} P} &= {l} + {w} + {l} + {w}\\\\ 90} &= {27} + {w} + {27} + {w} \\\\ 90} &= {54} + {w} + {w}\\\\ 36 &= {w} + {w} \end{aligned}$ What number can we add twice to get $36$ ? The width of the rectangle is ${18}$ centimeters.